Most traction control systems are designed to limit either wheel skidding or wheel slipping. The systems that limit wheel skidding help to decelerate vehicles by preventing wheels from rotating slower than required for maintaining adhesion with a traction surface, and the systems that limit wheel slipping help to accelerate vehicles by preventing drive wheels from rotating faster than required for maintaining the same adhesion. However, some more complicated traction systems are designed to limit both wheel skidding and wheel slipping.
Such traction control technology has been available for many years, and the advantages of this technology are widely known. Nevertheless, most automobiles are manufactured without electronic traction control systems for limiting either wheel skidding or wheel slipping, and a much smaller percentage of automobiles are manufactured to limit both. One reason for this may be the high cost of manufacturing traction control systems to operate with a degree of reliability required to supersede driver control over a vehicle. For instance, systems for limiting wheel skidding periodically take control over vehicle brakes. Systems for limiting wheel slipping periodically take control over either engine output power or its distribution to the drive wheels.
Although drivers may not be capable of responding as rapidly or effectively as advanced traction control systems to changes in vehicle operating conditions, at least some improvement to driving performance may be possible by alerting drivers to the detection of an impending loss of traction. This information about an impending loss of traction is available from traction control technology at a small fraction of the cost of a complete traction control system, because the driver retains responsibility for taking remedial action.